Process for treating textile materials



Feb. 28, 1961 s. BACKER ETAL PROCESS FOR TREATING TEXTILE MATERIALSFiled Aug. 15, 1957 STRETCHING ZONE' INVENTORS STANLEY BACKER I TNORDHAMMER FIG. 5, PER G05 A O S C ATTORNEY reach the. rollsbetweenwhich they pass. elongation of the material willv thus be reducedbut the PROCESS FOR TREATING TEXTILE MATERIALS Stanley Backer, Waban,and Per G. Nordhammer, Cambridge, Mass., assignors to Crompton & KnowlesCorporation, Worcester, Mass., acorporation of Massachusetts Filed Aug.13, 1957, Ser. No. 677,872

Claims. (CI. 26-54) This invention relates to improvements in methodsand means for treating textile and other sheet materials in such manneras to improve their dimensional stability, softness, hand, drapability,crimp, bulk, stretch, creping effect, etc. in a single operation.

Many textile and sheet materials do not drape satisfactorily and have ahard unfavorable surface, and shrink significantly in normal use. It isan important object of the present invention to provide a methodandmeans for acting on materials during or subsequent to theirformationor processing in conventional manner'to improve their qualitiesas above noted.

It is a further object of the invention to subject textile material,such as fibres, yarns, webs and fabrics, or other sheet material, to atreatment which will stretch them at the early stage of the process ortreatment and then cause them to become crimped or otherwise modified inthe latter part of the process.

In carrying the invention 'into effect we have found that esirablechanges can be produced in textile materials by passing them betweencompressible media or belts, or the like, such as rubber, these beltsbeing-driven by rolls or the like which cause compression of the belts'sufiicient to set up a high frictional contact with the textilematerial. As the latter is fed into the bight between the twocompressible media the textile material is elongated beyond its elasticlimit due to lengthwise extension of the media and because of theirfrictional contact with the textile material. As the belts or elasticmedia pass beyond their stage of maximum compression they begin tocontract in an effort to recover their original form and in doing soproduce a crimping or shortening effect on the textile material whichgives the latter improved qualities. The degree to which the desiredqualities are imparted to the textile materials can be varied partly bychoice'of the materials themselves and partly by the pressure exerted onthem by the rubber belts.

It is a further object of the invention to provide means for varying thelength of the textile material after-it has been acted on according tothe present invention. If. for instance it is' desired that the.material subject to treatment shall be shortened this result. can beaccomplished by: a .relative increase in thecontraction of the materialwhen the compressive force is reduced on the belts and this is attainedby 'pretensioning the latter beforev they The relative contractingeffect. will remain. the same so that propertionately there will be agreater shortening than the preflit d S et- S Patent 0. 5

2,972,795 Patented Feb. 28, 1961 ice vious stretching. The pretensioningcan in fact be high enough so that little or no extension of the beltsoccurs, in which case the shortening of the material is the principal,or sole result. If, on the other hand, it is desired to lengthen thematerial the belts are post-tensioned after they leave the rolls so thattheir contraction will be reduced and the crimping or shortening of thematerial will be less in proportion to its previous stretching.

The post tensioning can be high enough so that little or no contractionoccurs, in which case the lengthening or stretching of the material isthe principal or sole result.

In order that the invention may be clearly understood reference is madeto the accompanying drawing which illustrates by way of example twoembodiments of the invention and in which:

Fig. l is a diagrammatic view showing the mechanism for carrying theinvention into effect,

Fig. 2 is an enlarged diagrammatic view illustrating the manner in whichthe elastic media or belts are laterally compressed to causelongitudinal extension and then later in the process, upon reduction ofcompression, contract in the longitudinal direction,

Fig. 3 is a Z-part view showing a yarn before and after treatmentaccording to the invention, without preor posttensioning,

Fig. 4 is also a 2-part view but showing, as one example, a fabricbefore and after being treated according to the invention,

Fig. 5 is a diagram showing the different stages of treatment of atextile material, as an example, according to the invention.

Referring to Fig. 1, upper and lower rolls 10 and 11 are driven bygearing 12 so that they rotate in opposite directions as indicated bythe arrows. A 'set of three upper guide rolls indicated at 13, 14 and 15support a belt 16 which is preferably made of soft elastic rubber, andother lower guide rolls 17, 18 and 19 similarly support an elastic belt20. Each of the belts 16 and 20 may in fact be made of more than one plyand in one experiment which was performed each of the three plies wasslightly more than A3 thick.

The textile material to be acted on according to the invention is shownat T and is fed in from the left and is discharged at T at the right.Suitable supports for the material T, T can be provided although theyare not shown herein. The feeding of the textile material through themachine is accomplished by the rotation of the belts 16 and 20.

Fig. 2, which shows on an enlarged scale those parts illustrated in Fig.1 which have a more immediate bearing on the operation of the invention,shows the belts 16 and 20 of reduced thickness at 21 caused by the factthat the distance between adjacent surfaces of the rolls 10 and 11 isnoticeably less than the combined original or normal thickness of thetwo belts 16 and 20. The belts are therefore subjected to lateralcompression between the rolls and this compression results in theirlongitudinal elongation while they are in frictional contact with the.textile material T. This material is therefore stretched as. it passesbetween the rolls and as the belts reach a point beyond or to the rightof a line joining the axes ofthe rollsas viewed in Fig. 1, they begin torecover their original thickness as at and indoingsocontractlongitudinally while still in frictional contact with the textilematerial. It is this contraction which produces the shortening orcrimping of the textile material and this latter action is effectedbefore the belts move far enough apart to lose their contact with thematerial.

As a result of the stretching due to the elongation of the rubber beltsand then shortening or crimping due to the contraction of the belts thetextile material is found to have a much improved quality, being softerand more stretchable and in the case of a fabric possessed of improveddraping qualifies.

Fig. 3 shows the preferred form of the invention wherein a single yarnhas been treated by the process, this yarn shown at 25 and at the leftof Fig. 3 is in its original form and at the right in the form it hasafter being treated. We have found that a yarn so treated has beenincreased in length, and also has improved qualities of softness, bulk,crimp and stretchiness. In other yarns treated the length of the yarnhas remained unchanged or shortened, while retaining the other qualitiesmentioned.

in Fig. 4 the fabric 26 at the left is an untreated, nonwoven specimen,while that at the right illustrates the character of the fabric after ithas been treated according to the invention. Other fabrics, especiallythose including plastic fibers, which we have produced have one or moreof the qualities already described for the yarn shown in Fig. 3.

If two different kinds of fibers are used in a nonwoven fabric, such asthose of a nylon and a viscose variety, the stronger type 28 having thehigher extensibility exnot only produces the irregular pattern effectindicated in Fig. 4, but acts also as a soft filling.

, varied depending upon the kinds of fibers or materials used. Heat alsohas the advantage of facilitating the Fig. 5 shows diagrammatically thesuccessive stages '7 through which the textile material passes whenbeing submitted to the treatment set forth herein. The material isassumed to travel in the direction of the arrow and'the part designatedat O is the original untreated fiber, yarn or fabric before it reachesthe rubber belts. During the first part of the contact which thematerial has with the belts" it is subjected to a tensioning orstretching which is represented at S in Fig. 5. As the materialcontinues to f move along with the rubber belts it is then contracted orcrimped as at C during the stage of the operation when the belts recovertheir original form.

While the belts have been shown astravelin-g'around i rolls 10 and 11,it is to-be understood that the invention at least somewhat beyond itselastic limit so that it cannot recover its original length when theelastic media contract. This failure to recover original length on thepart of the material provides a length which results in the shorteningor buckling and crimping represented at- C in Fig. 5. This conditiondoes not necessarily exist when post-tensioning is present, as will nowbe described.

The invention can also be utilized to change the density of a fabriceither by a'longitudinal compressing or a stretching operation. If forinstance a fabric requires'to be reduced in length in order to meetspecifications then the extension of the fabric during the operationshould be reduced so that the proportion of the contraction will beincreased. This result may be attained by pretensioning the elasticbands 16 and 20 before they reach the rolls 10 and 11. If, on the otherhand, it is desired to stretch the material the bands 16 and 20 willthen bev post-ten sioned after they leave the rolls 10 and 11.

4 Preor post-tensioning of the belts 16 and 20 is effected by pinchrolls 15a and 19a which are driven either faster .or slower dependingupon whether post-tensioning or pretensioning is desired. When rolls 15aand 19a feed the belts faster than their peripheral rate at the nipbetween rolls 10 and 11, a pull results on those parts of the beltsmoving toward rolls 13 and 17 to cause the post tensioning alreadymentioned. When rolls 15a and 19a feed the belts slower than their rateat the nip a pretensioning results. These rolls 15a and 19a can bedriven by any suitable drive means.

From the foregoing it will be seen that the invention sets forth animproved method and means for first stretching a textile material andthen contracting it all in one operation in a sandwich calendering whichincludes feeding the textile material between two elastic media whichare first subjected to lengthwise extension while in frictional contactwith the material and are then permitted to contract while still infrictional contact with the material. The elastic media need notnecessarily be in the form of the belts shown nor will it be necessaryin all instances that the media travel around the rolls 10 and 11 ortheir equivalents. The thickness of the belts 16 and 20 and also theirinherent degree of compressibility may be varied to produce end resultsdesired in the textile material. Thus, for instance, if the belts arecomparatively thick they will produce a relatively wide nipping area forthe textile material having a degree of compression and the likelihoodof slip between the textile material and the elastic media will bereduced. If desired, heart may be applied to the material by heaters 30.Heat has the advantages of causing the material to act more as a plasticand less elastic to facilitate crimping or shortening of the material,and the heat provided by the heaters can be stretch of the materialduring the first part of the process.

The relative plasticity of textile fibers is also affected by theirmoisture content. If desired, the textile material entering the processcan be presprayed or steamed by nozzles or other conventional devicesnot pictured in Fig. 1'. The effect of increasing the fiber moisturecontent is to facilitate the stretch of the material during the firstpart of the process, and in the second part of the process to facilitatethe compressive shortening or crimping action as well as to increase thepermanence of the textile material modifications resulting from thetreatment.

-Having now particularly described and ascertained the nature of theinvention and in what manner the same is to be-performed, what isclaimed is:

1;. The method of treating a flexible fibrous structure, consisting inthe following steps: feeding each of two elastic deformable media arounda center and by a reduction of their thickness causing them as they movetoward a line joining the centers to be progressively deformedlengthwise in the direction in which they move and then as they moveaway from said line to progressively recover from their lengthwisedeformation, feeding a fibrous structure between said media and causingthe latter: to establish frictional contact with the fibrous structure'and stretch the material elements of the structure beyond their tensileelastic limit as the media move toward said line and then forcing thestructure to effective- 1y recover its over-all length by the media asthe latter recover from their deformation, the fibrous structureundergoing its stretching and recovery while in frictional contact withthe media.

2. The method set forth in claim 1 including the step of moving themedia toward each other so that each deforms and elongates the surfaceof the other in contact with the fibrous structure to stretch thelatter, and thereafter moving the media away from each other to enablethe surfaces contacting the fibrous structure to contract to shorten thelatter.

3. The method set forth in claim 2 wherein the media are under greaterlongitudinal tension when they are moving toward each other than whenthey are moving away from each other.

4. The method set forth in claim 2 wherein the media are under lesslongitudinal tension when they are moving toward each other than whenthey are moving away from each other.

5. The method of treating textile material consisting in the followingsteps: feeding the material between parts of elastic compressible mediaunder tension which are moving toward a stretching zone, compressing themedia at the zone to expand the media to longitudinally establishfrictional contact with the material to stretch the 5 latter.

References Cited in the file of this patent UNITED STATES PATENTSWrigley et a1 Nov. 26, 1935 2,522,663 Chatfield Sept. 19, 1950 FOREIGNPATENTS 376,040 Great Britain July 7, 1932

